Document Type

Article

Publication Date

September 2017

Publication Title

Open Journal of Acoustics

Volume

7

Issue Number

3

First Page

69

Last Page

82

DOI

10.4236/oja.2017.73007

ISSN

2162-5794

Keywords

Cochlea, Masking, Otoacoustic Emissions, Suppression, Humans

Disciplines

Communication Sciences and Disorders | Speech and Hearing Science | Speech Pathology and Audiology

Abstract

Stimulation of medial olivocochlear (MOC) efferent neurons reduces basilar membrane (BM) sensitivity and increases the slope of BM input-output (I/O) functions in animal models. Decreased compression of I/O functions associated with activation of MOC efferent neurons may assist in extending the neural response to the tone above that of noise, leading to an improvement in masked thresholds. To evaluate this hypothesis, the distortion-product otoacoustic emission (DPOAE) I/O function, a proxy measure of BM compression, was examined in conditions with presentation of contralateral noise. DPOAE I/O functions were measured at f2 frequencies of 1000 and 2000 Hz in 16 normal-hearing adults. In each subject, estimation of masked thresholds at 1000 and 2000 Hz was provided by a two-interval forced-choice procedure. There were statistically significant associations between DPOAE I/O function slopes and masked tone thresholds at both 1000 and 2000 Hz. At 1000 Hz, individuals with higher DPOAE I/O function slopes exhibited lower masked thresholds. Data at 2000 Hz indicated that individuals with higher masked thresholds exhibited higher DPOAE I/O function slopes. When measured with contralateral noise, DPOAE I/O function slopes were linked to masked thresholds at both frequencies examined in this study. Linearized DPOAE I/O functions presumably reflect linearized BM growth functions under conditions of MOC efferent activation, and this process may have extended the neural response to the signal tone so that it could be more easily heard in the presence of masking noise under certain conditions examined in this study.

Comments

Copyright © 2018 by authors and Scientific Research Publishing Inc. This article was published in the Open Journal of Acoustics, volume 7, issue 3, 2017 and can also be found online at this link.This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

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